Tumblr sold itself to Yahoo not too long ago, then Yahoo went on a spending spree, and then Tumblr hit headlines again when data hinted that being purchased by Yahoo may have seriously crimped Tumblr’s growth. The blogging site had been growing quickly for ages, partly due to the free-form, free-for-all nature of its posts, and we can guess partly because it was an ad-free experience. That’s changing. Fast.

There is now a special Tumblog entitled, cheekily, “Marketr,” which is all about helping brands establish an identity on the blogging platform that they “can be proud of,” and use to “build a passionate audience, and leverage the best native ads since Days Of Our Lives.”

Then there’s the “Tumblr A-List,” a selection of ad agencies that Tumblr thinks its potential brand partners may like:

To further enable brands to have the best Tumblr experience possible, Tumblr has introduced a grouping of our premiere advertising agencies, media agencies, creative agencies, technology providers and theme developers. Brands are increasingly experiencing Tumblr as the most unique and engaging way to participate in creative storytelling with consumers. Tumblr’s A-List partners are fully equipped with the right tools to provide their clients the ultimate Tumblr experience.

Given the extremely mixed reaction expressed by social media commenters after Yahoo’s acquisition of the once-youthful Tumblr, could the introduction of what seems to be pretty intensive ad campaign dampen enthusiasm for Tumblr?